| 近年来非洲热带Sahel地区持续干旱和厄尼诺现象增多的主要原因 |
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| 引用本文： | 徐群.近年来非洲热带Sahel地区持续干旱和厄尼诺现象增多的主要原因[J].热带气象学报,1987(3):274-280. |
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| 作者姓名： | 徐群 |
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| 作者单位： | 江苏省气象科学研究所 |
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| 摘 要： | 近年来世界气候异常在低纬度的表现十分突出,这就是引起大范围饥馑的热带西非的持续干旱和赤道东太平洋上增多的厄尼诺(E1—Nino)现象,本文通过分析发现,它们都和北半球太阳直接辐射自六十年代以来渐趋减少的趋势密切联系。由于1963年以来火山活动进入活跃期以及大气中人工气溶胶含量的日益增长,两者都促使北半球太阳直接辐射呈现稳定降低的趋势;夏半年减少的大陆加热量就会迫使夏季风减弱、北半球副热带高压及ITCZ均趋向偏南,从而在西非和赤道东太平洋分别促成了Sahel区的持续干旱和El—Nino现象的增多趋势。近年来我国华北盛夏雨量的减少估计也与此有关。这类气候特征且有可能在今后较长时间内继续维持。
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| 收稿时间： | 1986/11/13 0:00:00 |
| 修稿时间： | 2/2/1987 12:00:00 AM |
THE MAIN CAUSE OF THE PERSISTENT DROUGHTS IN SAHEL OF TROPICAL AFRICA AND THE INCREASING EVENTS OF EL-NIÑO FOR RECENT YEARS |
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| Xu Qun.THE MAIN CAUSE OF THE PERSISTENT DROUGHTS IN SAHEL OF TROPICAL AFRICA AND THE INCREASING EVENTS OF EL-NIÑO FOR RECENT YEARS[J].Journal of Tropical Meteorology,1987(3):274-280. |
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| Authors: | Xu Qun |
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| Institution: | Jiangsu M eterological Institute |
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| Abstract: | Climatic anomalies ocurring during recent years have showed their outstanding peculiarities at low latitudes, the persistent Sahel droughts and frequent occurrences of El-Nino events at east equatorial Pacific are the most notable features of them. By analyzing, it is found that these variations are closely related with the decreasing trend of direct solar radiation of N.H since 1960s, this trend is mainly caused both by the acceleration of volcanic eruptions and the successive increase of anthropogenic aerosols during recent years. The lowering of heating amounts on continents of N.H during summer half year certainly will influence the developing process of summer monsoon. This has expressed through southerly shifting of Northern subtropical-tropical atmospheric systems.Both Sahel persistent droughts and more E1-Niño years were thus caused by the southerly shifting ITCZ at west Africa and equatorial east Pacific separately since 1960s. The deficiency of summer rainfall of North China having succeeded for recent 2 decades is also related with the southerly displacement of west Pacific high. Finnally, present report further outlooks that such trend of climatic anomalies tend to persist in the next few decades. |
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